Apparatus for crimping and drawing yarn

ABSTRACT

A continuous one-pass apparatus for drawing and crimping synthetic polymer yarn. Heated, undrawn yarn is forwarded to a crimper at a predetermined, critical angle of contact with the crimping members thereof in order that the yarn be evenly drawn immediately before and during the crimping process.

United States Patent Martens [151 3,636,600 [451 Jan.25, 1972 1 APPARATUS FOR CRIMPING AND DRAWING YARN I72 Inventor; John J. Martens, Roundaal, Netherlands [73] Anlgnee: American Enkl Corporation, Erika, N .C.

[221 Filed: July so, 1968 [21] Appl. No.: 748,690

301 Foreign Application Priority pm Aug. 4, 1967 Netherlands ..6710832 Feb. 14, 1968 Netherlands ..6802063 [52] U.S.C1 ..28/1.8,28/72.15

[51] Int. Cl ..D02g 1/14 [58] Field of Search ..28/1.8, 72.15

[56] References Cited UNITED STATES PATENTS 3,256,134 6 1966 R:e gs 72.1595

3,192,597 7/1965 Mclntosh et a1 ..28/1.8 3,293,843 12/1966 Bibby et a1. ...28/1.8 X 3,299,485 1/1967 Hills et a1... ..28/72.15 X 3,408,717 11/1968 Bryant et a1. ...28/72.15 3,462,811 8/1969 Burgess et a1 ..28/1.S X

FOREIGN PATENTS OR APPLICATIONS 532,411 10/1956 Canada ..28/1.8 780,755 8/1957 Great Britain.. ..28/72. 15 6,705.606 7/1967 Netherlands ..28/1 :8

Primary Examiner-Robert R. Mackey Attorney-Francis W. Young ABSTRACT A continuous one-pass apparatus for drawing and crimping synthetic polymer yarn. Heated, undrawn yarn is forwarded to a crimper at a predetermined, critical angle of contact with the crimping members thereof in order that the yarn be evenly drawn immediately before and during the crimping process.

10 Claims, 9 Drawing Figures PATENTEUJANZSISTZ 3.836.600

sum 1 or 3 u IIII INVENTOR. JQHAN J MERTENS PATENTEBJANZSBYZ 3.836.600

sum 2 or 3 I NV ENTOR JOHAN J. MERTENS APPARATUS FOR CRIMPING AND DRAWING YARN This invention relates to apparatus for drawing and crimping of synthetic yam. More particularly, the invention relates to an improved one-pass apparatus wherein a heated yarn, at constant speed and tension, is subjected to mechanical deformation by guiding it along substantially a zigzag path and at a predetermined, critical angle of contact with a coacting crimping means. The crimping means consist of, for example, a pair of intermeshing gears turning at a speed which is slightly higher than or at least equal to the speed at which the heated, undrawn yarn is being supplied thereto.

Known methods of combined yarn drawing and mechanical deformation have the disadvantage in that variations in yarn tension occur in the zone found immediately beyond the crimping members and such variations are translated back upstream to the crimping and drawing zone. As a direct result thereof, the yarn products obtained show insufficient crimp, evenness of crimp and often are nonuniformly drawn.

An improved apparatus is obtained according to the invention which avoids the above drawback and results in an evenly drawn and sufficiently crimped yarn by a one-pass apparatus. In brief, an improved combined drawing and crimping apparatus is realized which permits imparting even drawing tension immediately before and during crimping when using coacting, intermeshing crimpers; a well-crimped and evenly drawn yarn is obtained by drawing partially before and partially between, for example, an intermeshing gear crimping member or the like. Described more in detail, the apparatus of the invention comprises means for passing undrawn synthetic polymer yarn to a heating means, thence along a zigzag path in contact with interrneshing crimping means such as a pair of coacting gears, teeth, pins, blades, and the like having a speed that is at least equal to or slightly higher than the speed at which the yarn is being supplied, and wherein the total angle of contact of the yarn with the crimper is at least radians. The-draw ratio of the yarn is determined by the yarn speed between the crimper relative to'the yarn supply'speed. The yarn speed between the crimping members is measured at the point of the maximum angle of contact therewith.

The yarn obtained is not only evenly drawn, but is also permanently crimped, i.e., corrugated, along its length.

In a preferred embodiment of the apparatus according to the invention, the yarn tension in the zone immediately following the crimping members, that is, the zone between the crimping members and the windup device, will therefore be maintained virtually constant. It is observed that the yarn tension in the zone will not deviate from a constant value by more than approximately 10 percent.

If the evenly drawn and highly crimped yarn is to be taken up on a ring twister, the rotary speed of the spindle thereof can, in a simple manner, be adjusted during winding so that the balloon tension above the traveler will remain virtually constant. With advantage, the yarn processed according to the invention need be passed between the intermeshing crimpers only once.

It is desirable that, in the zone or area beyond thecrimpers and before the takeup means, the yarn be advanced at a speed which is about one and/or one and one-half times the speed of the crimpers. Further drawing in the zone is to be avoided.

After having been drawn and crimped and before being wound, it is one preferred embodiment of the invention that the yarn again be heated while relaxed, i.e., without significant tension being placed thereon. The tension during such reheating should be lower than 0.001 gram per denier.

It has also been found that a crimped yarn of better quality in regard to crimp contraction, voluminosity, covering power and hand, can be obtained if the yarn is heated. in saturated steam of 100 C. while in the relaxed condition. A zigzag crimped yarn will result having an angle between neighboring sides of the zigzag smaller than 90' and generally about 80. Moreover, the crimp obtained is uniform along a selected length of the yarn. Satisfactory hand and the favorable properties of the products manufactured therefrom are obtained if the transitional portion between neighboring sides of the zigzag is of a thickness, for example, 5-l5 percent, smaller than atthe other points of the zigzag.

"In certain cases and particularly if the yarn is to be wound onto a spool with zero twist, it is also preferred that it be air tangled and interlaced, preferably in the zone following the crimper members and before takeup.

The apparatus includes a frame constructed to support a plurality of like yam feed mechanisms (for undrawn-uncrimped yarn), a zone in which the yarn to be treated can be heated, an intermeshing crimper, and appropriate means for yarn collection are suitable. Gear wheels having toothedwheel construction are preferred as the crimping means and wherein, on the pitch circle of each of the gears, the acute angle between the tangent to the tooth flank and the radius of the pitch circle is smaller than 15 and preferably is about l0. In a preferred embodiment, the circular pitch of each gear ranges between 0.500 to 0.950 mm.- On each gear, the thickness of each of the teeth, measured along the pitch circle, is about 0.200 mm. and the height thereof ranges between 0,450 to 0.950 mm. Optimum results are obtained providing the teeth of the two cooperating gears, measured along their common diameter, intermesh over a distance ranging between 0.350 and 0.550 mm.

It, surprisingly, has been found that textile yams crimped with gears having the above configuration show a higher crimp contraction, i.e., a greater difi'erence between the crimped length and the noncrimped length than yarns manufactured using conventional gear crimpers. Evenly drawn and wellcrimped yarn having a relatively high crimp contraction can be manufactured continuously in a particularly economic and effective way by such construction.

The principles of this invention, as well as other objects and advantages thereof, will clearly appear from a description of the preferred embodiment as shown in the accompanying drawings, in which:

FIG. 1 shows an apparatus according to the invention;

FIG. 2 shows the path of the yarn between the crimping members:

FIG. 3 shows the way in-which the yarn runs in angular contact with the crimping members;

FIGS. 4, 5, 6 and 7 show various other embodiments of the aforementioned apparatus;

FIG. 8 shows, on a highly enlarged scale, a few interrneshing teeth of a pair of crimping gears of the invention; and

FIG. 9 shows, on a strongly enlarged scale, the crimped yarn according to the invention.

With the setup shown in FIG. 1, undrawn yarn l is unwound end-over-end from spun package 2 by driven feed rollers 3 and 4 via the thread guide 5. Thereafter the yarn is given one or more wraps around heated plate 6, after which it passes between the teeth (not shown) of two gears 7 and 8. Depending on the desired draw ratio, the circumferential speed of the gear 7 and 8 is 1.4 to 2 times that of feed rollers 3 and 4. As illustrated in FIGS. 2 and 3, the yarn travels between gears 7 and 8 along approximately a zigzag path.

Downstream of gears 7 and 8, drawn yarn 9 is advanced by a driven roller 10 coacting with separator idler roller 11. It is imstream of the gears is not determined by the speed of roller 10.

After leaving driven, yarn forwarding roller 10, and upon passing through eyelet 12, the yarn is, in a conventional manner bya ring twisting spindle, wound onto package 13. Package 13 is shown having both-ends tapered and is supported by tube 14. Ring 15 traverses vertically and carries revolving traveler 16.

FIG. 2 shows, schematically, the zigzag path 17 of the yarn between the crimping members, that is, between the teeth of gears 7 and 8. The purpose of the inscribed circles at gears 7 and 8 is to be explained below and the circles are illustrated in partial section by the broken lines identified with numerals 18 and 19, respectively. As shown in the Figure, the yarn is passed between the gear teeth only once. The gear teeth are shaped in a manner so that between all the intermeshing teeth 20 there is left sufficient clearance on all sides so that the yarn will not be clamped between tooth sides or flanks but is gripped only by the tips of the teeth as it passes in contact therewith (as illustrated by FIG. 3).

It, surprisingly, has been found that favorable results are obtained if the total angle of contact of the yarn between the gears is at least 20 radians but preferably about 40 radians. Total angle of contact is the angle equal to the sum of the angles a a a a a,,, (1,, etc., (see FIG. 3), made by the yarn path 17 at each end of teeth 20 with reference to the tangents 21, 22, 28, etc., of circles 18 and 19 in the middle of the tooth faces. The angle of 1 radian is equal to an angle at the center of a circle subtended by an arc whose length is equal to the radius.

In one preferred embodiment, circles 18 and 19 were 60 mm. in diameter, and each gear carried 300 teeth.

In FIGS. 4 and 5 like parts are referred to by like numerals.

FIG. 4 shows a modification and differs from that shown in FIG. 1 in that the driven roller and the freely rotatable separator roller therefor are omitted. The rotary speed of the ring spindle, and hence that of bobbin 14, must be adjusted so that the tension of the yarn balloon remains approximately constant.

In the embodiment shown in FIG. 5, tangling means 24 is positioned downstream of gears 7 and 8. A turbulently flowing fluid is supplied thereto (in the direction indicated by the arrow) for tangling and interlacing the yarn filaments. The fluid can be air, steam or an inert gas. After the yarn has left tangling means 24, it is formed into the flat cross-wound package, indicated at 25. Roller 26 is in frictional contact therewith for v the purpose of driving package 25. Yarn traversal is provided in a known manner and in the direction indicated by arrow 27.

FIG. 6 shows another embodiment of the invention. Therein the feed rollers 3 and 4 shown in FIGS. 1, 4 and 5 are replaced by tensioning means 29 of known construction. Constant tension on yarn leaving the means is realized by its use. Downstream of gears 7 and 8, the apparatus of FIG. 6 may be similar to the apparatus shown in FIGS. 1, 4 and 5.

With the setup shown in FIG. 7, undrawn yarn l is, via thread guide 5, unwound end-over-end from package 2 by driven feed rollers 3 and 4. The yarn subsequently is passed over or around hot plate 6, after which it arrives between the teeth (not shown) of the two gears 7 and 8. Depending on the desired draw ratio, the circumferential speed of driven gears 7 and 8 is 1.4 to 2 times that of feed rollers 3 and 4. As indicated in FIG. 2, the yarn travels between gears 7 and 8 along approximately a zigzag path.

Downstream of gears 7 and 8, drawn yarn 9 is advanced with the aid of driven roller 10, of which the circumferential speed is about one and one-half times that of gears 7 and 8. Yam 9 is given a few wraps around roller 10 and the cooperating separator roller 11. The pulling force applied to the yarn by the yarn forwarding roller 10 downstream of gears 7 and 8 is such that yarn 9 is not appreciably drawn any further. The drawing tension in the yarn, between the crimper and feed rollers 3 and 4, is not influenced by yarn forwarding roller 10.

After leaving roller 10 and separator roller 11, the yarn arrives between a pair of intermeshing large-toothed gears 30, 31. The gears rotate at a speed which causes the yarn to slip between the teeth thereof so that the yarn is under tension upstream between feed rollers 3 and 4 and the gears. Tension downstream of the gears 30 and 31 is negligible.

In the tensionless zone downstream of the gears, the yarn is aflerheated. Heating device 32, comprising, for example, a plurality of electric heating elements (not shown), is suitable. Afterheating the yarn without tension will, for the most part, completely develop crimp inserted by crimping gears 7 and 8.

At the end of the secondary or afterheating, the yarn is passed several winds over the driven forwarding roller 33 and separator roller 34.

Finally, and after passing through top eyelet 12, the yarn is conventionally wound on package 13 with the aid of a ringtwisting spindle. Ring 15 traverses vertically and supports traveler 16.

While the Figures show only one position for treating yarn according to the invention, in practice the apparatus will comprise several like positions, all attached to one frame or support.

FIG. 8 shows, on an enlarged scale, a few teeth which are positioned symmetrically about gears 7 and 8 having a common diameter. The pitch circles of gears 7.and 8 are indicated at the broken lines of partial circles 35 and 36, respectively. As will be observed, the two gears 7 and 8 have involute teeth and the acute angle between a tangent to the tooth flank and the radius of curvature of the pitch circle is, according to the invention, preferably 10. The root circles of gears 7 and 8 are indicated at 37 and 38, respectively. The circular pitch (=arx module) of gears 7 and 8 is indicated at 39 and 40, respectively. The thickness of the teeth measured along the pitch circle is indicated at 41 and 42, respectively, and the working depth of the gears is indicated at 43. In one particular embodiment of the apparatus according to the invention, the number of teeth of each crimping gear was 300, and the module was 0.20, so that the diameter of the pitch circle was z m= 300X0.2()=60.00 mm. In the embodiment the working depth 43 of the gears was 0.380 mm., and the diameters of the inscribed circles 18, 19 and root circles 37, 38 were 60.420 mm. and 59.378 mm., respectively.

FIG. 9 shows, on an enlarged scale, the appearance of one filament of yarn crimped according to the invention and is taken from yarn that has been unwound from a bobbin and heated in a relaxed state in steam of C. The yarn is found to possess a very regular crimp. With the yarn shown in FIG. 9, the angle between neighboring sides 46, 47 of the zigzag is about 70. At the transitional portions 48 between neighboring sides of the zigzag, the thickness of the filament is 5-15 percent smaller than at the other points of the zigzag.

It will be apparent that the embodiments shown are only exemplary and that various modifications can be made in the construction and arrangement thereof within the scope of the invention as defined in the appended claims.

What is claimed is:

1. An apparatus for continuous one-pass manufacture of synthetic polymer yarn crimped in a substantially zigzag pattern having a transitional portion between the sides of the zigzag crimp that is smaller than the remaining segments of yarn comprising the zigzag, comprising:

a. at least one yarn feeding means for supplying uncrimped,

undrawn yarn;

b. a yarn heating means;

c. a pair of driven gears downstream of said feeding means and heating means having a plurality of intermeshing teeth for crimping and drawing the heated yarn during one pass between the gears, said driven gears having on the pitch circle of each gear an acute angle smaller than 15 between the tangent to the gear tooth flank and the radius of the pitch circle, and said gears intermeshing over a distance smaller than 1mm. and having sufl'icient clearance on all sides so that the yarn is gripped only by the tips of said teeth, with the total angle of contact of the yarn between the gears being at least 20 radians and preferably about 40 radians; the configuration, speed and arrangement of said gears being such that the yarn is crimped to provide said zigzag pattern; and

d. means for withdrawing the drawn, crimped yarn from the gears under substantially constant minimum tension so that further drawing of the yarn is avoided.

2. Apparatus according to claim 1 wherein the angle is about 10.

3. Apparatus according to claim 1 wherein the circular pitch of each gear is smaller than I mm.

4. Apparatus according to claim 3 wherein the circular pitch ranges from 0.500 to 0.950 mm.

6 5. Apparatus according to claim 4 wherein the circular teeth is between 0.450 and 0.950 mm. pitch is 0.628 mm. 9. Apparatus according to claim 1 wherein the teeth inter- 6. Apparatus according to claim 1 wherein the thickness of mesh to a depth ranging between 0350 and 0550 mm teeth on each of said gears is smaller than 0.500 mm.

7. Apparatus according to claim 6 wherein the thickness is 5 ApParatus accordmg to clam l whefem the teeth of the gears are mvolute and the module thereof is 0.20.

about 0.200 mm.

8. Apparatus according to claim 6 wherein the length of the 

1. An apparatus for continuous one-pass manufacture of synthetic polymer yarn crimped in a substantially zigzag pattern having a transitional portion between the sides of the zigzag crimp that is smaller than the remaining segments of yarn comprising the zigzag, comprising: a. at least one yarn feeding means for supplying uncrimped, undrawn yarn; b. a yarn heating means; c. a pair of driven gears downstream of said feeding means and heating means having a plurality of intermeshing teeth for crimping and drawing the heated yarn during one pass between the gears, said driven gears having on the pitch circle of each gear an acute angle smaller than 15* between the tangent to the gear tooth flank and the radius of the pitch circle, and said gears intermeshing over a distance smaller than 1mm and having sufficient clearance on all sides so that the yarn is gripped only by the tips of said teeth, with the total angle of contact of the yarn between the gears being at least 20 radians and preferably about 40 radians; the configuration, speed and arrangement of said gears being such that the yarn is crimped to provide said zigzag pattern; and d. means for withdrawing the drawn, crimped yarn from the gears under substantially constant minimum tension so that further drawing of the yarn is avoided.
 2. Apparatus according to claim 1 wherein the angle is about 10*.
 3. Apparatus according to claim 1 wherein the circular pitch of each gear is smaller than 1 mm.
 4. Apparatus according to claim 3 wherein the circular pitch ranges from 0.500 to 0.950 mm.
 5. Apparatus according to claim 4 wherein the circular pitch is 0.628 mm.
 6. Apparatus according to claim 1 wherein the thickness of teeth on each of said gears is smaller than 0.500 mm.
 7. Apparatus according to claim 6 wherein the thickness is about 0.200 mm.
 8. Apparatus according to claim 6 wherein the length of the teeth is between 0.450 and 0.950 mm.
 9. Apparatus according to claim 1 wherein the teeth intermesh to a depth ranging between 0.350 and 0.550 mm.
 10. Apparatus according to claim 1 wherein the teeth of the gears are involute and the module thereof is 0.20. 